Documentation (and detailed installation instructions) can be found online at the
Puppet Docs site.

Installation

Generally, you need the following things installed:

A supported Ruby version. Ruby 1.8.7, and 1.9.3 are fully supported.

The Ruby OpenSSL library. For some reason, this often isn't included
in the main ruby distributions. You can test for it by running
ruby -ropenssl -e "puts :yep". If that errors out, you're missing the
library.

If your distribution doesn't come with the necessary library (e.g., on Debian
and Ubuntu you need to install libopenssl-ruby), then you'll probably have to
compile Ruby yourself, since it's part of the standard library and not
available separately. You could probably just compile and install that one
library, though.